Machine Learning Vasicek Model Calibration with Gaussian Processes

In this article, we calibrate the Vasicek interest rate model under the risk neutral measure by learning the model parameters using Gaussian processes for machine learning regression. The calibration is done by maximizing the likelihood of zero coupon bond log prices, using mean and covariance functions computed analytically, as well as likelihood derivatives with respect to the parameters. The maximization method used is the conjugate gradients. The only prices needed for calibration are zero coupon bond prices and the parameters are directly obtained in the arbitrage free risk neutral measure.     

Curation: a theoretical treatment

Curation is a key mechanism of sociality in a digital era. With an abundance of information, sifting, sorting, selecting, hiding, and standing out become laborious tasks. While researchers have diligently documented people’s curatorial strategies, digital curation remains undertheorized in its own right. I therefore theorize digital curation by disentangling productive curation from consumptive curation, addressing how people curate content that they share, and that which they consume. I embed these agentic curatorial practices within structural bounds, both social and technological. In doing so, I offer a basic theoretical model that captures a dynamic relationship between individual curators, their social networks, and technological design.     

数字化生存的道德风险与信息崇拜的伦理考辨

当代人尤其是青年人面临诸多现实世界中自我难以解决的矛盾和困惑时,期许能在电子＂伊甸园＂中找回自我价值和精神皈依。然而,虚拟空间并非想象中的天堂,类似＂面具＂的交流形式遮蔽着许多本真的存在,消解了现实世界的核心价值;游离在虚拟和现实之间的自我与社会脱离;对网络的过渡依赖性导致人格的异化;方向感的迷茫和自我定位的偏差,使得价值追求从崇高滑向流俗甚至恶俗。数字化生存方式正颠覆着传统生活方式和现实生活世界的诸多价值标准,而信息崇拜的推波助澜,更使人们产生了一种莫名的幸福被剥夺的感觉。     

New politics and satire: the Euro financial crisis and the one-finger salute

ABSTRACT

This article argues that the conventional conceptualization in political science of politics is problematic, that it is overly narrow and constrained. This is because it excludes a range of actions like satire and humour which have come to play an increasing role in inspiring and provoking powerful political emotions and in informing the political agenda. Drawing on the work of critical scholars, it is argued that emotion, ethics and art can be deeply political. Moreover, new forms of media have encouraged new–old forms of political action often at the hands of young people who hitherto have been marginalized from the public sphere. Digital technology enables the production of user-generated content, opening new spaces for information, the exchange of ideas and mobilization. This article highlights the work of the young German satirist Jan Böhmermann to demonstrate how expressive art is playing a major role in shaping public opinion, in contesting power elites and informing political debate. In short, I use Böhmermann’s 2015 satire depicting Greco-German relations in the midst of a financial crisis and fears of loan defaults to argue for a broader understanding of politics that is inclusive of activities conventionally deemed non-rational.     

新媒介背景的儿童类纸质媒体发展取向

数字媒介技术的革新加剧了“图像革命”，造成了人的思考能力的滑坡．这一影响加之于儿童则更加明显。儿童作为特殊且脆弱的社会群体，极易陷入新媒介所搅动的文化漩涡中，传统阅读这一儿童基础性认知技能遭遇到严峻考验。儿童类纸质媒体应充分发挥独有优势，与儿童类数字媒体展开错位竞争。从儿童文化内容的创作生产、儿童文化产品的销售渠道、儿童文化消费的最终实现三个层面完成自身的发展与跨越。     

Assistive technology for disabled visual artists: exploring the impact of digital technologies on artistic practice

Abstract

Disabled artists with physical impairments can experience significant barriers in producing creative work. Digital technologies offer alternative opportunities to support artistic practice, but there has been a lack of research investigating the impact of assistive digital tools in this context. This article explores the current practice of physically impaired visual artists and their experiences around the use of digital technologies. An online survey was conducted with professional disabled artists and followed up by face-to-face interviews with 10 invited artists. The findings illustrate the issues disabled artists experience in their practice and highlight how they are commonly using mainstream digital technologies as part of their practice. However, there is little awareness around novel forms of technology (e.g. eye gaze tracking) that present new creative opportunities. The importance of digital tools for supporting wider practice (i.e. administrative and business tasks) was also highlighted as a key area where further work is required.     

基于盾构掘进参数的LVQ神经网络地层识别

以苏州4号线2标及2号线东延伸线5标地铁工程为背景，分析了盾构机的掘进参数：千斤顶推力、推进速度、刀盘扭矩、螺旋机转速和同步注浆量在不同地层条件下的变化规律。提出了基于盾构机掘进参数的学习向量量化（Learning Vector Quantization，LVQ）神经网络地层识别方法。建立了以盾构机五个掘进参数作为输入，地层特性编码为输出的数学模型，通过每种地层100组训练样本对模型进行训练，通过57步训练，训练样本误差控制在0.1以内，并用每种地层50组检验样本进行检验，地层总体识别率达到82.7%。     

Navigating the technology-media-movements complex

Abstract

In this article we develop the notion of the technology-media-movements complex (TMMC) as a field-definition statement for ongoing inquiry into the use of information and communication technologies (ICTs) in social and political movements. We consider the definitions and boundaries of the TMMC, arguing particularly for a historically rooted conception of technological development that allows better integration of the different intellectual traditions that are currently focused on the same set of empirical phenomena. We then delineate two recurrent debates in the literature highlighting their contributions to emerging knowledge. The first debate concerns the divide between scholars who privilege media technologies, and see them as driving forces of movement dynamics, and those who privilege media practices over affordances. The second debate broadly opposes theorists who believe in the emancipatory potential of ICTs and those who highlight the ways they are used to repress social movements and grassroots mobilization. By mapping positions in these debates to the TMMC we identify and provide direction to three broad research areas which demand further consideration: (i) questions of power and agency in social movements; (ii) the relationships between, on the one hand, social movements and technology and media as politics (i.e. cyberpolitics and technopolitics), and on the other, the quotidian and ubiquitous use of digital tools in a digital age; and (iii) the significance of digital divides that cut across and beyond social movements, particularly in the way such divisions may overlay existing power relations in movements. In conclusion, we delineate six challenges for profitable further research on the TMMC.     

In search of African history: the re-appropriation of photographic archives by contemporary visual artists

The digital revolution has fundamentally changed our relationship to archives, by accelerating their “dusting off” and their re-appropriation, particularly in the art world. This article will show the ways in which some contemporary visual artists use new digital technologies to provide new ways of storing, reading and retrieving contemporary African history. Such artists do so by revisiting diverse forms of archives that are mainly photographic, and which were produced during the colonial and independence eras.     

Digital media,subcultural activity and youth participation: the cases of protest rap and graffiti in Portugal

Over the last decade, we have witnessed the emergence of an academic debate surrounding the relationship between youth and the ‘new media’, with a particular emphasis on the social uses of different digital technologies within the sphere of youth activity. A specific area of research has been dedicated to studying the use of digital media in the context of the so-called youth subcultures. With this article we expect to contribute to this ongoing debate, by examining the problem through an analysis of two interconnected case studies: protest rap and illegal graffiti. Both cases may be defined as subcultures, insofar as they are characterized as alternative, subterranean, and to a certain extent, subversive movements. The empirical ground for this discussion is based on several investigations, with a qualitative basis, carried out by the authors in the course of over a decade in Portugal. This extended time frame allowed ample access to a diversified and matured analytical material and enabled a better perspective of the developments and the mutations involving the appropriation of the digital media. Our researches have shown that digital media and technologies have been gradually integrated in these urban youth subcultures, accomplishing several strategic roles.